Infrared imaging to detect components on personal care articles

ABSTRACT

This invention pertains to fabricating composite personal care article products on a fabrication line, and sensing assembly quality characteristics of such personal care article products so fabricated, using infrared image sensing apparatus, and signal processing apparatus for processing the infrared energy so sensed, to fabricate visual displays of the composite images sensed by the infrared sensing apparatus. By using infrared imagery, and sensing the various temperatures of elements being placed and worked on the fabrication line, elements of the personal care articles which are hidden from visual observation can be sensed by sensing the infrared radiation emitted from such articles. Elements which are available for visual observation can likewise be sensed where temperature of such elements is suitable for detection, by infrared-sensitive receptors. Typically, a suitable infrared signature can be obtained without adding, to the elements whose quality is being assessed, any increment of heat for purposes of enhancing detection of such element or elements.

CROSS REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

FIELD OF THE INVENTION

This invention relates to an improved inspection and quality levelsensing system for use during processing of webs such as paper, film,composites, or the like, in dynamic continuous processing operations.More particularly, the invention relates to sensing and assessing thelocation and quality condition of features, characteristics, andelements characteristic of personal care articles or precursors of sucharticles on an article fabrication line. The invention can sense andassess, for example, the location and quality of respective components,the location and quality of ultrasonic or thermal bonding, and/or thelocation and amount of adhesives present in a web of personal carearticle precursors during the fabrication of such personal care articleprecursors from suitable raw material inputs.

BACKGROUND OF THE INVENTION

In assembling various elements on an e.g. endless web to make personalcare articles, it is highly desirable to have a real-time inspection ofvarious aspects of the articles being fabricated, including inspectionof the articles at one or more locations on the fabrication line, as thearticles are being fabricated and before fabrication is complete.

In the personal care article industry, it is known to use opticalbrighteners to mark components or portions of elements which form sucharticles in a fabrication line. When such optical brighteners areproperly selected, properly applied, and properly positioned, thearticles can be illuminated with ultraviolet light and/or visible light.Ultraviolet and visible light sensors can sense the optical brightenersso illuminated, and can thus record the positions, or relativepositions, of components carrying such optical brighteners in suchpersonal care articles. While some article elements can thus bedetected, to applicants' knowledge, it is not known to employ suchprocedures to assess presence and quality of adhesive or other bonds orbonding in the context of a personal care article.

In addition, applicants are aware that some, but not necessarily all,hot melt adhesives inherently fluoresce under ultraviolet light.However, applicants are not aware of any use of such property fordetecting relative positioning of elements.

In other methods of assessing or predicting product quality, structuralelements such as notches, slits, slots, protrusions, depressions, orholes or the like are formed in the web of personal care articles, thusto provide a detectable structural feature which can be used to senselocation of an element.

A region of magnetic discontinuity, electromagnetic discontinuity, orany combination thereof may also be used with suitable sensors ofmagnetic properties to show the positions of components of respectivepersonal care articles.

The above methods of assessing or predicting product quality requiremodifying the personal care articles specifically for the purpose ofbeing able to sense or detect the parameters of interest, such as forexample using additional material such as an optical brightener, or amagnetic additive, or modifying the structure of the personal carearticles, in order to create an element detectable by the sensorsselected for the detection function. Such modifications increase thecost of personal care articles, in addition to bearing the cost of theactual detection. Further, use of such additional material, elements, orfeatures includes the risk that the additional material, elements, orfeatures, may be misplaced in the web, or on the respective web element,and thus give a false reading to the sensing system. There is also therisk that such modification to the product or product component mayinterfere with either the intended use of the personal care article orthe safety of a person using the personal care article for the intendeduse.

It would be desired that no such additional material element, orfeature, need be incorporated into or added to any element or feature ofthe articles being fabricated.

SUMMARY OF THE DISCLOSURE

In the invention, process heat with which the workpiece elements areinherently imbued by the process, is detected by one or more infraredsensors which sense the thermal condition inherent in a plurality ofcharacteristics of respective features of the personal care articlesbeing formed, and wherein the features so sensed generally have primaryutility in the typical functioning of the article, and are notincorporated into the article merely to assist in the sensing operation.Characteristics which are sensed are, for example, individualcomponents, and parts of components, of the personal care article,ultrasonic bonds, and adhesive at bonds. With proper resolution in adisplay of the properties so sensed, sensing such elements can pinpointor show the exact location of such individual components, or adhesive,or ultrasonic or other thermally-formed bonds. The sensed informationcan be compared to stored or other reference information to determinewhether or not the respective components or bonds are disposed atdesired or specified locations on respective personal care articles.

The sensed information also can be compared with stored or otherreference information to determine whether or not the qualities orstrengths of ultrasonic bonds are effective to maintain the structuralintegrity of the respective personal care articles.

Further, the sensed infrared information can be compared with stored orother reference information to determine whether or not a sufficientquantity of adhesive, such as hot melt adhesive, has been applied to thepersonal care articles being fabricated and whether or not such adhesivehas been properly distributed, in the proper relationships, on therespective components of the personal care articles.

The above comparisons can be reported to a fabrication line operatorwhereby the operator can monitor ongoing conformity with, or variancefrom, reference or other specified parameters. Variance outsidespecified tolerances can trigger an alarm to warn the operator that amalfunction has occurred. Further, the above comparisons can be used tocull unacceptable units of product from the personal care articlefabrication line. Information from the above comparisons can also beused to shut down the processing line at certain predetermined levels ofvariance from specified parameters.

A significant advantage of the invention is that infrared sensors cansense the location of elements which are not readily susceptible todetection from the outside of the personal care article using sensorsoperating in the visible or ultraviolet wavelengths. Because of use ofthe infrared spectrum, the infrared system can see elements orcomponents through one or more layers of material which are opaque tovisible and/or ultraviolet light. Thus, assuming an infrared energysource, an infrared sensor can “see through” e.g. cover layers orbodyside liners of material and can display visual images of elements orcomponents thus “seen” or detected on the interior of the personal carearticle. In this manner, partially or fully assembled personal carearticles can be viewed or inspected for defects which may be disposedunder a visually opaque element. Processing apparatus, such as a digitalcomputer, can process the received information and compare theinformation with reference or otherwise known tolerances and physicalvalues for the various components, and positions of components.

The infrared sensor typically comprises a passive infrared sensor thatsenses, in the personal care article work product, or work productprecursor, heat that is normally inherently present in the personal carearticle or work product or precursor as a result of the process ofassembling such work product or precursor. The heat results from, forexample, ultrasonic bonding, the application of hot melt adhesive tovarious components of personal care articles, and residual heatotherwise developed in others of the elements as the elements areprepared for, and incorporated into, the personal care articles beingfabricated on the fabrication line.

For example, certain components, such as the absorbent core, andsuperabsorbent therein, are inherently heated, or can be heated, totemperatures different from the temperatures of other components wherebysuch elements can be distinguished on the basis of temperaturedifferences. Namely, a component can be distinguished in the visualdisplay by controlling temperature of the component such that thecomponent emanates infrared radiation at a rate which is unique in theweb, relative to other components of the personal care articleprecursor.

To the inventors' knowledge, it is not known to utilize an infraredsensor to sense fibrous and/or thin-section polymeric films, fibers, oradhesives as components in a personal care article fabrication line,thereby to provide signals or information in response to the physicaltemperatures of components forming the personal care articles,especially where the property sensed, namely temperature, is theproperty inhering in the personal care article precursor in thefabrication line as a result of the manufacturing process, ormanufacturing history, of the precursors. Of course, at conclusion ofthe manufacturing process, the personal care articles so producedcontinually give off heat according to temperature differentials betweenthe personal care articles and ambient temperature, until the personalcare articles reach ambient temperature. Thus, the infrared signaturesof interest herein must be obtained while the personal care articlesstill contain discriminating amounts of such process heat.

Further to the inventors' knowledge, it is not known to use an infraredsensor to sense infrared energy and thereby to create visual imagescorresponding to the presence or quantity of adhesives, or strength ofultrasonic bonds, on the personal care articles. Advantageously, warmadhesives can be seen by the infrared sensor through one or moreintervening visually opaque layers of material in the personal carearticle.

The above reading of infrared signatures can be obtained by placingsuitable assemblage of infrared sensor equipment at a single sensinglocation in the fabrication line. Multiple images of the articles beingproduced on the fabrication line can, of course, be obtained by placingsuitable assemblages of infrared sensor equipment at a correspondingnumber of locations along the fabrication line, each of such assemblageshaving the capability of sensing the desired information at therespective locations in the fabrication line, from which a visual imagecan be created, separate and distinct from the visual images developedfrom sensings at other locations along the fabrication line. Suchmultiple images, taken from corresponding multiple locations on thefabrication line, can be compared to each other as desired for assessingeither or both of (a) quality of the articles being produced, and (b)the satisfactory, or not, progression of the fabrication process alongthe fabrication line.

A first family of embodiments of the invention contemplates fabricationapparatus for fabricating composite personal care article products, andsensing assembly quality characteristics of the personal care articleproducts so fabricated. At least one of the components of precursors ofthe personal care article products so fabricated comprises a continuousweb of material. The fabrication apparatus comprises fabricationmachinery arranged to transport the web along a fabrication line, past aplurality of work stations where work is performed on the web, forfabricating the personal care article precursors according to apredetermined arrangement, thereby to form an array of precursors ofsuch personal care articles on the web; separation apparatus separatingthe web, and the array of personal care article precursors thereon, fromthe web, and into individual personal care articles, including severingthe web across a transverse dimension thereof; and infrared sensing andsignal processing apparatus disposed in cooperating relationship withthe web. The infrared sensing and signal processing apparatus sensesinfrared signatures of product fabricated on the web, therebydetermining assembly quality characteristics of respective ones of thecomposite personal care articles or composite personal care articleprecursors, and outputting a signal representative of the sensedcharacteristics.

In some embodiments, the infrared sensing and signal processingapparatus comprises an infrared sensor housed in a housing physicallyseparate and distinct from the signal processing apparatus, such thatthe sensor and processing apparatus are two physically separate anddistinct instruments. The processing apparatus receives a signaloutputted from the infrared sensor and processes such signal to providea processor output representative of the characteristics of at least oneof the personal care articles or personal care article precursorsfabricated on the fabrication line.

The fabrication machinery can place an absorbent core on the web, and abodyside liner material over the absorbent core such that the absorbentcore is between the web and the bodyside liner layer, and the infraredsensing and signal processing apparatus can view and sense the positionof the absorbent core through the bodyside liner material, through theweb, or through any other intervening material which may be visuallyobstructive, such as opaque, translucent, occlusive, or the like andthat is not a thermally-effective barrier to detection by a thermalsensor or other thermal detection unit.

As another expression of the invention, the bodyside liner material canhave a visual printed image on a first surface thereof between theinfrared sensor and an assembly quality characteristic under therespective one of the bodyside liner material and the web, the sensingby the infrared sensor sensing an assembly quality characteristicthrough the visual printed image.

The invention also comprehends securement apparatus such as ultrasonicbonding apparatus or adhesive bonding apparatus securing at leastportions of the respective components of the personal care articles toeach other to form the composite personal care article precursors in acontinuous web of such precursors joined to each other along a length ofthe web. Thus, the invention comprehends adhesive application apparatusapplying adhesive for securing at least first portions of firstrespective components of the personal care articles to second portionsof second respective ones of the components.

In some embodiments, the infrared sensor senses the position of adhesivein such personal care articles. In addition or in the alternative, theinfrared sensor senses quantities of adhesive disposed in such personalcare articles.

The personal care articles can include leg elastic placement apparatusplacing spaced leg elastics adjacent respective opposing outside edgesof leg cut-outs of the web along the lengths of the personal carearticles, and adhering the leg elastics to components of the web or onthe web. Adhesive apparatus can place hot melt adhesive on the legelastics, the infrared sensor sensing the position of the heated hotmelt adhesive on the leg elastic and thus indirectly detecting thepositions of the leg elastics on the personal care articles by way ofthe warm hot melt adhesive.

In preferred embodiments, the bodyside liner material is disposedbetween the infrared sensor and the leg elastics, and the infraredsensor senses the positions of the adhesive, and thus the positions ofthe leg elastics, through the bodyside liner material.

In some embodiments, the absorbent cores have zones comprising relativeconcentrations of superabsorbent, and the infrared sensor senses thezones of relative concentration of superabsorbent as distinct from theremainders of the absorbent cores.

In some embodiments, the fabrication machinery places containment flapsover the web, preferably over the bodyside liner material, as elementsof the personal care article precursors. The containment flaps aresecured in the web by heated hot melt adhesive or other thermal orultrasonic bonding. The infrared sensor senses position and quantity ofthe heated hot melt adhesive or other thermal or ultrasonic bonding.

The securement apparatus preferably comprises an ultrasonic horn andcooperating anvil, such as an anvil roll, the ultrasonic horn providingultrasonic energy to create bonds bonding, in the personal care articleprecursors, at least one component of such personal care articleprecursors.

The infrared sensor preferably senses the positions of the still-warmultrasonic bonds. The output of the infrared sensor can provide anindication to an operator station when the infrared sensor does notdetect the presence of the ultrasonic bonds.

Among other potential readings, the infrared sensor and signalprocessing apparatus can sense registration of predetermined ones of thecomponents, either against a design location stored in memory or,relatively, against the location of a second component or other element,characteristic of the articles, e.g. an adhesive or ultrasonic bond.

The output of the infrared sensing and signal processing apparatus cansend an alarm signal to an operator station identifying existence of animproper condition for at least one of the components, or can output acull signal to cull selected ones of the personal care articles from thefabrication line, or can shut down the fabrication line, or can issue acontrol command, and thereby activates a registration control function.

Stated another way, the output of the infrared sensing and signalprocessing apparatus can call attention, in various ways, tocharacteristics or components of the personal care articles that are notwithin preselected control tolerances.

The infrared sensing and signal processing apparatus can sense thepresence of leg cut-outs on the personal care articles, and control analarm to an operator station.

Typically, the infrared sensing and signal processing apparatus sensesand assesses assembly quality characteristics common to all of thepersonal care articles being fabricated on the fabrication line, theassembly quality characteristics, in combination, comprising a signaturefor the specific personal care articles being fabricated.

Preferably, the infrared sensing and signal processing apparatus has asensitivity suitable for sensing, and thus senses, portions, orentireties, of personal care articles having temperatures as low asabout 10 degrees Celsius and up to about 200 degrees Celsius.

Preferably, the infrared sensor is a single sensor or sensor array,operating in a passive mode, whereby no illuminating energy is directedtoward the material being sensed. Rather, the sensor senses temperaturesand differences across the overall projected surface defined by an areaof one or more of the personal care articles.

Typically, the infrared sensing and signal processing apparatuscomprises an infrared camera collecting infrared images from thepersonal care articles. Typical cameras effective to detect anddistinguish infrared radiation are controlled by the electronic andoptical filtering elements of the camera, or of one or more suitablecamera attachments.

In preferred embodiments, the output from the infrared sensing andsignal processing apparatus comprises a composite visual imagerepresentative of at least one of the personal care articles or personalcare article precursors on the web. Typically, the infrared sensorcomprises an infrared camera collecting, for each visual image which canbe displayed, an array of infrared signals from discrete areas of thepersonal care articles being assessed.

The output of the infrared sensing and signal processing apparatus canrepresent an out-of-tolerance condition in the personal care article orpersonal care article precursor sensed, and wherein the infrared sensingand signal processing apparatus sends the out-of-tolerance signal to anoperator station.

More specifically the fabrication machinery used in fabricating personalcare articles according to the invention can further comprise a firstlayer device and a first turning device, feeding the web into thefabrication line; an absorbent core device feeding absorbent cores tothe web in the fabrication line; a second layer device and a secondturning device, feeding a second outer layer into the fabrication lineand over the first layer and the absorbent cover; a leg elastics devicefeeding leg elastics into the fabrication line; a containment flapdevice feeding containment flaps into the fabrication line above thesecond outer layer; a first bonding device applying generally continuousbonds along opposing sides of the web along substantially the entiretyof the length of the web downstream from the bonding device; a secondbonding device applying end seals along ends of the respective personalcare article precursors; a first adhesive application device applyingadhesive to the leg elastics, thereby to adhere the leg elastics in thepersonal care article precursors; a tape storage device feeding tapesinto the fabrication line; a second adhesive application device applyingadhesive to the tapes, thereby to adhere the tapes in the personal carearticle precursors; and a third adhesive application device applyingadhesive to the containment flaps, thereby to adhere the containmentflaps in the personal care article precursors over the absorbent core.

In a second family of embodiments, the invention comprehends a method ofsensing assembly quality characteristics of a web of personal carearticles or personal care article precursors being fabricated on afabrication line by processing apparatus. Each such personal carearticle or personal care article precursor has a bodyside liner, anouter cover, and at least one element of the personal care article orpersonal care article precursor disposed between the bodyside liner andthe outer cover. The method comprises using infrared sensing and visionimage signal processing apparatus employing an infrared sensor, sensingassembly quality characteristics of an element, typically an elementbetween the bodyside liner and the outer cover, through a substantiallyvisually obstructive one of the outer cover and the bodyside liner,namely through a visually obstructive one of the elements whichprecludes facile visual observation of the respective qualitycharacteristics, and outputting first signals from the infrared sensor;and sending the outputted signals to an element of the infrared sensingand signal processing apparatus which can respond by outputting secondsignals indicative of assembly quality characteristics of the personalcare articles or personal care article precursors being fabricated bythe processing apparatus.

Preferred embodiments include maintaining the personal care articlesfree from fluorescent material, especially fluorescent materials andother additives for optical brightening as used for detection purposes,throughout the process of fabricating the personal care articles.

A third family of embodiments comprehends a method of fabricatingcomposite personal care article products wherein at least one of thecomponents of precursors of the personal care article products sofabricated comprises a continuous web of material, and wherein themethod comprises transporting the web along a fabrication line, past aplurality of work stations where work is performed on the web, forfabricating the personal care article precursors according to apredetermined arrangement, thereby to form an array of precursors ofsuch personal care articles on the web: separating web segments, and thearray of personal care article precursors thereon, from the web, andinto individual personal care articles, including severing the webacross a transverse dimension thereof; and sensing infrared signaturesof product fabricated on the web, thereby determining assembly qualitycharacteristics of respective ones of the composite personal carearticles or composite personal care article precursors, and outputting asignal representative of the sensed characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood and furtheradvantages will become apparent when reference is made to the followingdetailed description of the invention and the drawings, in which:

FIG. 1 is a schematic representation of a first embodiment of afabrication line including infrared sensor and signal processingapparatus of the invention.

FIG. 2 is a line drawing representative of a top view of an image of anunderlying web moving along the fabrication line, and as viewed by theinfrared sensor.

FIG. 3 is a schematic representation of a second embodiment of afabrication line, including infrared sensor and signal processingapparatus of the invention.

FIG. 4 is a cross-section of the underlying web, and thus of thepersonal care article precursor, taken at 4—4 of FIG. 2.

FIG. 5 is a cross-section of the underlying web, and thus of thepersonal care article precursor, taken at 5—5 of FIG. 2, with the legcut-out material removed.

FIG. 6 shows a pictorial view of a personal care article made accordingto the invention.

FIGS. 7 and 8 are pictorial representations of actual visual imagescreated and used in sensing assembly quality according to the invention.

The invention is not limited in its application to the details ofconstruction or the arrangement of the components set forth in thefollowing description or illustrated in the drawings. The invention iscapable of other embodiments or of being practiced or carried out inother various ways. Also, it is to be understood that the terminologyand phraseology employed herein is for purpose of description andillustration and should not be regarded as limiting. Like referencenumerals are used to indicate like components.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The following detailed description is made in the context of afabrication line for making personal care articles. Personal carearticles can include, without limitation, diapers, training pants,incontinence articles, feminine care articles, and the like.

FIG. 1 illustrates a fabrication line 10 for fabricating personal carearticles. Fabrication line 10 includes a first layer storage device 12storing a generally continuous length of a first web material to be usedas a first layer 14, and a turning roll 16 for turning first layer 14into alignment along the fabrication line.

Absorbent core forming device 18 forms absorbent cores 20 forapplication onto first layer 14. Turning roll 21 and drive roll 22 forma first nip 23. Drive roll 22 and support roll 24 form a second nip 25.Turning roll 21, drive roll 22, and support roll 24, in combination,transfer absorbent cores 20 from absorbent core forming device 18 ontofirst layer 14.

Leg elastics storage unit 26 stores leg elastics 28 and second layerstorage device 30 stores a generally continuous length of a second webmaterial to be used as a second layer 32, of material such as acontinuous web of bodyside liner material. Drive roll 34 and supportroll 36, in combination, form a third nip 38. Leg elastic adhesiveapplication device 40 generally intermittently applies adhesive to legelastics 28. Elastic securement roll 42, drive roll 34, and support roll36, in combination, apply leg elastics 28, and adhesive thereon, ontosecond layer 32. The process preferably cuts the leg elastic at e.g.roll 34 if the adhesive is applied continuously; but may not cut the legelastic, if the adhesive is applied intermittently, until a later stepin the process, such as at product cut-off. Second layer 32 and legelastics 28 are then joined to first layer 14 at nip 38. At nip 38,absorbent cores 20, as well as elastics 28, are disposed between firstlayer 14 and second layer 32 as illustrated in FIG. 5. At this stage,the above mentioned components have formed an underlying web 44 ofpersonal care article precursors 45.

At the next stage in the fabrication line, tapes or stretch ears 46,stored in a tape storage device 48, are secured to underlying web 44 byapplication roll 50. Adhesive application device 52 applies adhesive toportions of tapes 46 before the tapes are applied to underlying web 44.

A containment flap storage unit 54 then applies containment flaps 56along the full length of underlying web 44 on opposing sides ofabsorbent cores 20, via an application roll 58 and an opposing supportroll 60 at fourth nip 61. Containment flap adhesive applicator 62intermittently applies adhesive to containment flaps 56. The adhesiveapplied to containment flaps 56 is in registration with leading andtrailing end portions of the personal care article precursors 45 onunderlying web 44, such that the adhesive secures the full widths ofcontainment flaps 56 in web 44 at front and back waist portions ofpersonal care article precursors 45 and secures only outward edgeportions of containment flaps 56 in web 44 along the interveningmid-portions (crotch portions) of the personal care articles.

Thus, as illustrated in FIGS. 2, 4, and 5, outer edges 63 of containmentflaps 56 are secured in web 44 along the entire length of a givenpersonal care article precursor by a generally continuous bond 65.Correspondingly, inner edge 91 is bonded in underlying web 44 only atfront and back portions of the personal care article precursors (FIGS.2, 4), whereby the intermediate portion of the article precursor, namelyacross crotch portion 83, is not bonded to any underlying web element.Accordingly, when containment flaps 56 are relaxed, inner edges 91 canstand up along the mid-portion, namely crotch portion 83, whileremaining secured at bond 65 to materials of underlying web 44.

Underlying web 44, including tapes 46, containment flaps 56, and legelastics 28, then advances to ultrasonic horns 64 and supporting anvilroll or rolls 66. Ultrasonic horns 64 and anvil rolls 66 form a fifthnip 68 where outward portions of multiple components of underlying web44 are ultrasonically bonded to each other. In this manner, first andsecond parallel lines of ultrasonic bonding 88 are formed generallyalong the entirety of the length of underlying web 44, bonding firstlayer 14 and second layer 32 to each other along substantially theentire lengths of the respective webs downstream of nip 68. First layer14 and second layer 32 are preferably co-extensive along the entirelength, and across the entirety of the width, of underlying web 44,including between the first and second lines of ultrasonic bonding.

Underlying web 44 then advances to end seal ultrasonic horn 70. End sealultrasonic horn 70, in cooperation with anvil roll 72, forms a sixth nip74. At nip 74, ultrasonic horn 70 forms intermittent end seals 76 acrossportions of underlying web 44 corresponding to, and bridging, theleading and trailing end portions of succeeding ones of the respectivepersonal care article precursors.

At this point in the process, underlying web 44 has been substantiallytransformed into a series array of personal care article precursors,joined to each other at end seals 76, which later in the process formthe respective leading and trailing edges of the resulting personal carearticles. The major remaining steps comprise forming leg cut-outs to fitthe personal care article about the legs of a wearer, and severingacross underlying web 44 to thus form the leading and trailing edges ofthe above-mentioned leading the trailing end portions of individualpersonal care articles, and thereby to separate individual personal carearticles, including individual web segments, from the generallycontinuous web.

In this embodiment, underlying web 44 next advances past infrared sensor80. Infrared sensor 80 preferably comprises a passive infrared sensorsensing infrared radiation emanating from discrete areas of the personalcare articles being assessed. Sensor readings are thus taken fromvarious positions across underlying web 44 and along a pre-definedlength of the web. Namely, sensor 80 senses individual radiation ratesat closely spaced locations across the full width of the web, thus toprovide an array of readings representing a comparative temperatureprofile across the width, and along a specified portion of the length ofthe web. Infrared sensor 80 does not retain, record, or report visiblelight, or ultraviolet light received from the underlying web.

Sensor 80, optionally in combination with signal processing apparatus82, converts the individual radiation readings sensed along the lengthand width of the web into a composite visual image representing thewidth, and the specified portion of the length, of the web on a visualdisplay screen, such as a computer monitor or the like, illustrated byoutline 81 in FIG. 2. FIG. 2 is a line drawing representation of thevisual image so displayed, showing a top view of a section of underlyingweb 44, on the monitor. The image shown includes a first full personalcare article precursor 45A, a major portion of a second precursor 45B,and a minor portion of a third precursor 45C. FIGS. 7 and 8 arereproductions of actual visual images produced according to theinvention, showing fabrication of personal care articles in a continuousweb process, and illustrating visibility of elements such as leg elasticwhich are hidden from visual observation by the overlying cover layer32.

The different temperatures, or otherwise stated the different rates ofemanating infrared energy from the several elements of web 44, and thusprecursors 45, create respective different shades of gray in the visualimage displayed (FIGS. 7, 8), or of color on a color image display,whereby at least the outlines of the respective elements are clearlydistinguished from each other in the displayed visual image.

For example, in this embodiment, FIG. 2 illustrates at arrow 79 thedirection of advance of web 44, and shows absorbent cores 20. Whileabsorbent cores 20 are illustrated in dashed outline in FIG. 2, theoutline of the cores can be clearly displayed as part of the visualimage created from the sensing of infrared energy, even though secondlayer 32 overlies the entirety of the respective absorbent cores andthus blocks visual detection of the outer edges of the absorbent cores.Absorbent cores 20 are readily detected by infrared sensor 80 becauseabsorbent cores 20 typically have a different temperature than eitherfirst layer 14 or second layer 32.

Such image of absorbent cores 20 and other elements of underlying web 44is utilized by sensor 80 and/or processing apparatus 82 to define asignature for the products being fabricated, including a signature fore.g. absorbent cores 20 relative to the rest of the elements ofunderlying web 44. Such a signature can be defined as a distance, from aside edge running along a portion of the length of the absorbent core,e.g. to an edge of underlying web 44, to an edge of first layer 14, orto an edge of second layer 32. Such distance can be compared totolerance values (distances) in a predetermined or preselected rangewhich determine positioning of the several elements of web 44 relativeto each other.

The signature can also be defined in terms of the absolute temperature,for example the amount of infrared radiation being received, from thearticle being sensed, thus to monitor and control the absolutetemperature of one or more of the elements being sensed, thus to detectoverheating, or excessively cool, conditions.

If one or more of the positions of respective absorbent cores 20, orother elements, with respect to other elements of underlying web 44, areout of the preselected range, processing apparatus 82 can send a controlsignal to the respective element placement devices, such as absorbentcore device 18 and/or drive roll 22 to adjust the positioning of e.g.the absorbent cores at first layer 14. Positioning of other elements canbe similarly adjusted.

Signal processing apparatus 82 can, in addition or in the alternative,provide an audible or visual warning, to an operator station 104, andthus to a fabrication line operator, that e.g. absorbent cores 20 arenot being placed at proper positions on first layer 14.

A second preselected range greater than the first preselected range canalso be utilized for providing a second type of response to thecondition sensed. For example, if absorbent cores 20 are out of positionfrom other components by the distance set forth in the secondpreselected range, individual units of product can be culled either bythe operator or by command of signal processing apparatus 82, orfabrication line 10 can be shut down and production discontinued untilrepairs or adjustments are made.

Signal processing apparatus 82 preferably includes a computer controllersuch that preselected ranges for the distances between ones of theelements can be monitored. For example, a distance between an edge ofabsorbent core 20 and a second component of the web, such as an outeredge of the web along the length of first layer 14 or second layer 32,can be monitored, and changed or adjusted as necessary according toparameters set up in processing apparatus 82 or elsewhere in apparatusof the invention.

FIG. 2 illustrates superabsorbent zones 84 where superabsorbent materialhas been incorporated into cores 20. Superabsorbent material istypically used in particle form. The particles are typically heated andthus thoroughly dried, before being incorporated into core 20, andthence into web 44. Absorbent core device 18 (or other correspondingapparatus of known design) is conventionally configured to add theheated superabsorbent particles to one or more selected portions of theabsorbent cores used in fabrication line 10.

Such superabsorbent, being heat dried immediately prior to use, has atemperature greater than the temperature of absorbent core 20 ingeneral, and greater than the temperature at other adjacent portions ofunderlying web 44. Therefore, images of superabsorbent zones 84 wheresuperabsorbent material has been incorporated into the core can bedistinguished on the visual display from the core in general. Thus, thedetected locations of superabsorbent zones 84, and the intensity of thesignals sensed, can be compared to preselected or predetermined zonesand intensities, by processing apparatus 82. Processing apparatus 82 canthen send control signals to absorbent core device 18 to control theamount and location, of placement of superabsorbent in subsequentlyfabricated absorbent cores 20.

Processing apparatus 82 can provide an operator with a visual displayand/or a warning signal, and/or can make process condition adjustmentsand/or can shut down fabrication line 10 as described earlier withrespect to absorbent cores 20 upon any detection of an out-of-tolerancecondition, by issuing suitable commands through feedback lines 87.

FIGS. 2 and 7 illustrate leg elastics 28 in underlying web 44. In theembodiment illustrated, stretched leg elastic material is fed ascontinuous strands from storage unit 26. Adhesive is applied along theleg elastic material. Leg elastics 28 are then incorporated into web 44,and secured to second layer of the personal care article precursorsbeing formed along underlying web 44. As described earlier with respectto absorbent cores 20, infrared sensor 80 can sense the differencebetween the temperature of leg elastics 28 and adjacent elements, and insome cases can distinguish the adhesive, with respect to thetemperatures of other adjacent elements of web 44. Infrared sensor 80can provide such sensing even though one of first layer 14 and secondlayer 32 is positioned between leg elastics 28 and the infrared sensor.

By processing the data received by sensor 80, sensor 80 and/orprocessing apparatus 82 can establish an image signature representativeof the actual locations and sizes of elements of leg elastics 28, andcan compare the actual and relative locations and sizes of such legelastic elements to preselected stored values associated with suchlocations and sizes. As noted earlier with respect to absorbent core 20,processing apparatus 82 can send control signals to leg elastic storageunit 26 and/or adhesive application device 40 to adjust the positioningof leg elastics 28, or the amount or timing of intermittent applicationof hot melt adhesive to the leg elastics. In addition, or in thealternative, sensor 80 and/or processing apparatus 82 can provide anoperator with a visual display of the image signature and/or can providea warning signal, or can shut down fabrication line 10 in response tothe absence or misplacement, or poor bonding, or another impropercondition, of leg elastics 28.

Tapes 46, also known as stretch ears, generally comprise two or morelayers of material. If the multiple layers have not been previouslyjoined, adhesive application device 52 can apply adhesive to form orsecure the layers to each other, thus completing formation of tapes 46,and can apply adhesive for at least temporarily securing such tapes inweb 44. Pairs of tapes 46 can be intermittently applied to underlyingweb 44 at spaced locations on opposing sides of personal care articleprecursors 45 as shown in FIGS. 1 and 2. Tape application roll 50, orother apparatus (not shown) can comprise an intermittent motion orvariable speed device that periodically places discrete tapes on web 44at the appropriate spaced locations.

Adhesive, preferably comprising a hot melt adhesive, applied by adhesiveapplication device 52, forms intermittent tape bonds 86, shown in FIGS.2, 7, and 8, securing tape components to each other or securing layersof tape material to each other.

Likewise, containment flaps 56 can be positioned by application roll 58along the entire length of underlying web 44 adjacent opposing sides ofabsorbent cores 20 as shown in FIGS. 2, 7, and 8.

Ultrasonic horn 64 and supporting anvil roll 66, in combination,continuously form continuous ultrasonic structural bonds 88, bondingfirst layer 14 and second layer 32 to each other along opposing sides ofunderlying web 44 as illustrated in FIGS. 2 and 7. Structural bonds 88are preferably continuous along the length of web 44. By “continuous,”we include bonds which comprise a generally continuous array of separateand distinct, discreet bond elements, such as an array of dots spacedfrom each other in an array. Ultrasonic horn 64 also preferably formsultrasonic bonds between tapes 46 and underlying web 44 at spacedlocations along the length of web 44 where tapes 46 are incorporatedinto the web, and thus along the lengths of bonds 88. Such bonds, aswell as bonds 88, can be formed by any known bonding technique, such as,without limitation, ultrasonic bonding, adhesive bonding, or thermalbonding.

An adhesive applicator generally illustrated at 64, in combination withanvil roll 66, or other suitable apparatus, can also intermittentlyapply adhesive, and thus bond inwardly-disposed edges 91 of containmentflaps 56 to second layer 32 as at bonds 90. Such containment flap bonds90 are positioned at areas, along underlying web 44, which correspond tothe front and rear portions of personal care article precursors 45 beingformed, as illustrated in FIG. 2. Bonds 90 can, in the alternative, befabricated by suitable application of adhesive by application device 62.

With bonds 90 being formed only at the front and rear portions of thepersonal care article precursors, edges 91 are not bonded to layer 32 atthe crotch portions of personal care article precursors 45. Accordingly,containment flaps 56 can stand up, with edges 91 disposed away fromlayer 32 when the resulting, separated, personal care article is mountedon, thus to interface with the body of the wearer, and to deter leakageof exudates outwardly beyond containment flaps 56. FIG. 6. Aconventional containment flap elastic (not shown) generally extendsalong the length of inwardly disposed edge 91 of containment flap 56 toassist in erecting, or standing up, the containment flap against thebody of the wearer, thus providing a seal element against the body ofthe wearer.

While FIG. 1 shows a single ultrasonic horn 64 and single anvil roll 66bonding containment flaps 56 and tapes 46, such bonding can be done bymultiple ultrasonic horns (not shown) and/or multiple anvils. Forexample, multiple ultrasonic horns can be spaced along the length of web44 to form multiple bonds 86, 88, and 90 on opposing sides of web 44and/or elsewhere as desired. Ultrasonic horns separate and distinct fromthe horn illustrated at 64 can separately bond tapes 46 to underlyingweb 44.

From nip 68, web 44 then travels to nip 74 formed by end seal ultrasonichorn 70 and anvil roll 72. End seal ultrasonic horn 70, in combinationwith anvil roll 72, intermittently forms end seal bonds 76 across amajor portion of the width of underlying web 44 by bonding first layer14 and second layer 32 in the web, and preferably to each other. Duringfurther processing of web 44 (not shown), the web is completely severedacross its width whereby segments of the web defining individualpersonal care article precursors 45 are completely severed from the weband are thus formed into individual personal care articles 78. The lineof such severance is indicated at 94 in FIG. 2, intermediate the leadingand trailing edges of end seal bonds 76. Thus each end seal bond 76 isdivided by such severance into two parts. A first part of bond 76 sealsa rear waist of a leading personal care article precursor (e.g. 45B) anda second part of bond 76 seals a front waist of a respective trailingpersonal care article precursor (e.g. 45A).

In a step prior to severing web 44, leg cut-outs 96 are removed fromunderlying web by a cutting roll (not shown) or the like and removalsuction. Leg cut-outs 96 are illustrated by dashed lines at the crotchportions 83 of personal care article precursors 45A, 45B in FIG. 2. Suchleg cut-outs generally are made before web 44 is severed into individualpersonal care articles 78.

In another embodiment, shown in FIG. 3, infrared sensor 80 sensesunderlying web 44 after leg cut-out cutting device 98, working againstopposing roll 100, has cut leg cut-outs 96 and the waste material hasbeen removed from web 44. This embodiment generally operates in the samemanner as the embodiment of FIG. 1. However, processing apparatus 82,using an image developed from data collected by infrared sensor 80, cansense the presence, or absence, of ultrasonic bonds 88 in zonescorresponding to leg cut-outs 96. If such bonds 88 are present in thecrotch portion of precursors 45, processing apparatus 82 concludes thatthe leg cut-outs have not been successfully removed, and the severedpersonal care article is culled and an adjustment command is sent tosuitable elements of the fabrication machinery. If the conditionpersists, fabrication line 10 can be shut down by processing apparatus82. Further, the operator can be warned of the failure of leg cut-outcutting device 98 whereby he or she can personally intervene to assurethat appropriate corrective action is taken.

First layer storage device 12 preferably comprises a progressively woundroll of material corresponding to first layer 14. Storage device 12generally is designed to accommodate change-over rolls so that when afirst roll of layer 14 material is exhausted, the leading end of asecond roll can be automatically fed along with the trailing end of thefirst roll, so that feeding of first layer 14 can be changed over fromthe first roll as feed roll to the second roll as feed roll whilecontinuously feeding layer 14 material to fabrication line 10.

First layer 14 can comprise an outer cover of the personal care article.First layer 14 can be formed from a single layer, or from multiplecomponents, layers, or partial layers, of material, typically insurface-to-surface relationship with each other, such that the resultingouter cover is substantially impermeable to liquids. A typical firstlayer 14 can be manufactured from a thin plastic film or other flexibleliquid-impermeable material. For example, first layer 14 can be formedfrom a polyethylene film having a thickness of from about 0.012millimeter to about 0.051 millimeter.

When it is desirable that first layer 14 have a more cloth like feeling,layer 14 can comprise, for example, a polyethylene film laminated to anonwoven web, such as a spunbonded web of polyolefin fibers. Forexample, a polyethylene film having a thickness of about 0.015millimeter can have thermally or otherwise laminated thereto aspunbonded web of polyolefin fibers having a thickness from 1.5 to 2.5denier per filament, which nonwoven web has a basis weight of about 24grams per square meter. Further, first layer 14 can be formed of a wovenor nonwoven fibrous web which has been totally or partially constructedand/or treated to impart a desired level of liquid impermeability toselected regions that are adjacent or proximate absorbent core 20. Stillfurther, first layer 14 can optionally be composed of a micro-porousmaterial which permits vapors to escape from absorbent core 20 andthrough first layer 14 while preventing liquid exudates from passingthrough the first layer.

Absorbent core device 18 can comprise conventional apparatus which formsabsorbent cores that are positioned on first layer 14 by drive roll 22.Such absorbent core forming devices are well known in the personal careart.

Absorbent cores 20 suitably comprise a relatively thicker structure,compared to first layer 14 or second layer 32, and include a matrix ofhydrophilic fibers, such as a web of cellulosic fluff, preferably incombination with a high-absorbency material commonly known assuperabsorbent material. In a particular embodiment, absorbent cores 20comprise a mixture of superabsorbent hydrogel-forming particles and woodpulp fluff. In place of the wood pulp fluff, one can use synthetic,polymeric, meltblown fibers or a combination of meltblown fibers andnatural fibers. The superabsorbent can be substantially homogeneouslymixed with the hydrophilic fibers or can be otherwise combined into theabsorbent core to form superabsorbent zones 84 having relatively higherconcentrations of superabsorbent particles. Other configurations ofsuperabsorbent are also contemplated, but use of superabsorbent zones 84generally can provide for the best containment of body exudate fluids.

Alternatively, an absorbent core 20 may comprise a laminate of fibrouswebs and superabsorbent material or other suitable means of maintaininga superabsorbent material in a localized area.

Absorbent cores 20 can have any of a number of overall shapes. Forexample, the absorbent core can be rectangular, oval-shaped or themodified hour glass shape shown extend over the entire dimensions offirst layer 14 or second layer 32.

The superabsorbent material in absorbent core 20 can be selected fromamong natural, synthetic and/or modified natural polymers and materials.The high absorbency materials can be inorganic materials, such as silicagels, or organic compounds, such as crosslinked polymers. The termcrosslinked refers to any means for effectively rendering normallywater-soluble materials substantially water insoluble but swellable byaqueous fluid, whereby absorbent properties are available but theswelled material is substantially immobile after absorbing water-basedliquids. Such means can include, for example, physical entanglement,crystalline domains, covalent bonds, ionic complexes and associations,hydrophilic associations such as hydrogen bonding, and hydrophobicassociations or Van der Waals forces.

Drive roll 22 can comprise a conventional absorbent-transferring rollfor receiving and transferring absorbent cores 20 to first layer 14.

Leg elastics storage unit 26 can comprise a conventional elastics unitapplying first and second spaced elastics onto second layer 32 viaelastic securement roll 42.

Leg elastics 28 typically are pre-stretched before application to secondlayer 32. Materials suitable for forming leg elastics 28 includestrands, ribbons, or one or more layers of a polymeric and/orelastomeric material. Leg elastics 28 can suitably comprise one or moreindividual strands of elastomeric material. For example, a plurality ofelastic strands can be configured in a spatially separated, generallyparallel arrangement. A suitable elastic strand can, for example, becomposed of a 470 decitex LYCRA® elastomer, 620 decitex LYCRA® elastomeror other elastomers having suitable characteristics.

In other embodiments, leg elastics 28 can be intermittently applied inthe crotch portion of completed, and individually defined and separatedpersonal care articles 78.

In most embodiments, rear waist elastics (not shown) are contemplatednear end seal bonds 76 to enable the finished personal care articles 78to conform to and fit the body of any wearer having a waist size withina specified range of sizes. Such rear waist elastics can comprisestrands, ribbons, or one or more layers of a polymeric and/orelastomeric material, preferably a material which can be adhered topersonal care article 78 while the elastics are in a stretchedcondition. Rear waist elastics can comprise one or more individualstrands of elastomeric material, preferably in a spatially separated,generally parallel arrangement. While rear waist elastics can be made ofmaterials similar to leg elastics 28, the amount of retractive force,and generally the thickness of the respective elastic strands, or likematerial, is generally less.

Second layer storage device 30 preferably comprises a progressivelywound roll of material corresponding to second layer 32. Such device 30generally is designed to accommodate change-over rolls so that when afirst roll of layer 32 material is exhausted, the leading end of asecond roll can be automatically fed along with the trailing end of thefirst roll, so that feeding of second layer 32 can be changed over fromthe first roll as feed roll to the second roll as feed roll whilecontinuously feeding layer 32 material to fabrication line 10.

Second layer 32 can comprise a bodyside liner in the finished personalcare article. A suitable second layer 32 acting as a bodyside liner canbe manufactured from a wide selection of web materials, such as porousfoams, reticulated foams, apertured plastic films or natural orsynthetic fibers. For example, second layer 32 can comprise wood orcotton fibers. Other possible materials are synthetic fibers, such aspolyester or polypropylene fibers, or a combination of natural andsynthetic fibers. Second layer 32 can beneficially be utilized to helpisolate the aqueous body exudate liquids, which are held in absorbentcore 22, from the skin of the wearer.

In addition, various woven and nonwoven fabrics can be used for thebodyside liner. For example, the bodyside liner can be composed of ameltblown or spunbonded web of polyolefin fibers. The bodyside liner cancomprise a carded and/or bonded web composed of natural and/or syntheticfibers. The bodyside liner can comprise a substantially hydrophobicmaterial wherein the hydrophobic material is treated with a surfactantor otherwise processed to impart a desired level of wettability andhydrophilicity. In a particular embodiment of the present invention, thebodyside liner can comprise a spunbonded polypropylene fabric composedof about 1.0-3.2 denier fibers formed into a web having a basis weightof about 22 grams per square meter and a density of about 0.06 grams percubic centimeter. Such fabric is treated with about 0.3 weight percentof a surfactant.

Second layer 32 can comprise a bodyside liner having a multiplicity ofcomponents, layers, or partial layers, which correspond to any of thematerials disclosed herein, as well as others known in the art. Thebodyside liner can also comprise a plurality of the above mentionedmaterials in surface-to-surface relationship with each other.

In other embodiments, second layer 32 can comprise an outer cover andfirst layer 14 can comprise a bodyside liner. Such a reversal of websrequires corresponding changes in the layout of fabrication line 10 inorder to arrive at the same ultimate arrangement of elements.

Tape storage device 48 and application roll 50 can comprise conventionalelements known for positioning tapes 46 on an underlying web such as web44. While FIG. 1 illustrates tapes 46 being positioned on an uppersurface of second layer 32, namely an outer surface of the personal carearticles, in other embodiments, the tapes can be positioned between thefirst and second layers, or on an outer/lower surface of the firstlayer/outer cover.

Tapes 46 can comprehend stretch ears and can comprise any of a varietyof fastening elements. For instance, tapes 46 can comprise hook and loopfastener elements for securing a rear portion of personal care article78 to a front portion of the personal care article, in well knownmanner. Other well known securing elements can be used to supportpersonal care article 78 on the wearer. For example, a cohesive system,an adhesive fastener system, or the like can be utilized as securingelements, with suitable cooperating elements on the front portion of thepersonal care article, as necessary, to support personal care article 78on the wearer.

Containment flap storage unit 54, in combination with containment flapapplication roll 58 and support roll 60, can comprise a containment flapapplication system. Such a system can continuously apply containmentflap material along opposing sides of absorbent core 20, continuouslysealing the outer edges of the containment flaps to web 44 at secondlayer 32, and intermittently sealing the inner edge 91 so that thecontainment flaps are free to stand up at inner edges 91 only at crotchportions 83 of personal care articles 78. Containment flaps 56 can bemade in whole or in part of materials set forth for second layer 32.However, to prevent leakage of exudates transversely past thecontainment flaps, containment flaps 56 are preferably formed fromliquid impermeable materials set forth for first layer 14. Containmentflaps 56 can comprise multiple layers of material. In such anarrangement, some layers can be impermeable and others permeable, tobody exudate liquids.

Ultrasonic horns 64, 70 preferably comprise well known rotary ultrasonichorns such as the horns set forth in U.S. Pat. No. 5,110,403 to Ehlertissued May 5, 1992, the disclosure of which is hereby incorporated byreference in its entirety.

Adhesives applied by adhesive application devices 40, 52, 62 generallycomprise hot melt adhesives which are sufficiently hot to be fluid whenapplied, and which solidify as they transfer heat to the ambientenvironment and thereby cool down. The heat radiated from such elevatedtemperature adhesives is detectable by infrared sensor 80 even if theadhesives are covered by other elements of underlying web 44 whereby theadhesives are hidden from visual view. Thus, the positions andquantities of the several warm adhesives can in general be sensed byinfrared sensor 80 through other components of personal care articles78.

Personal care articles 78 typically comprise absorbent articles suitablefor absorbing and retaining body exudates. Such articles include,without limitation, disposable diapers, training pants, feminine carearticles, and adult incontinence products.

Infrared sensor 80 preferably comprises a passive infrared sensorsensing differences in temperature at positions along underlying web 44as the web moves along fabrication line 10. Namely, sensor 80 does notnormally rely on projecting any energy at underlying web 44 for thepurpose of enhancing the ability to sense respective elements of theweb.

However, while not the preferred embodiment, the invention doescontemplate that one or more of the elements to be detected can beheated, or cooled, specifically for the purpose of enhancing itsdetection, to a temperature which will enhance the viewer's ability todistinguish the respective element or elements in the visual imagedisplay.

Infrared sensor 80 does not record or retain visible light orultraviolet light from the underlying web. Infrared sensor 80 does notsense fluorescent material applied to the web. Specifically, preferredembodiments of this invention contemplate personal care articles 78being free from any (e.g. fluorescent) material applied for the purposeof being detected as representative of the presence and positioning ofone or more elements of personal care article precursors 45 onprocessing line 10.

On the other hand, this invention does comprehend creating a singlecomposite visual image from signals received from a combination ofsensors comprising an infrared sensor and one or both of a visual sensorand an ultraviolet sensor. In the case of using visual or ultravioletsensors in combination with infrared sensor 80, any e.g. visual orfluorescent material known to be coated/painted onto an article to bedetected, for the purpose of enhancing detection, can also be used inthis invention for assisting detection by the respective visual orultraviolet sensor.

Infrared sensor 80 generally comprises an infrared vision camera.Examples of suitable cameras are e.g. Model 575 from AGEMA InfraredSystems AB, Danderyd, Sweden, and INFRAMETRICS SC1000 Therma CAM byINFRAMETRICS, INC. of North Billerica, Mass.

Any apparatus used as sensor 80, optionally in combination withprocessing apparatus 82, should have suitable discrimination capabilityto suitably define the outlines of the several elements of web 44 in thevisual image. Accordingly, sensor 80, or a combination of suitablesensors, and processing apparatus 82 as appropriate should be able todistinguish elements of at least 0.5 mm in size, and to detect thelocations of component edges to a resolution of not less than 0.5 mm,thereby to provide a clear infrared signature indicating the relativelocations of the respective elements on web 44.

Infrared energy suitable for being sensed according to the invention, bysensor 80. is defined as having a wavelength or frequency of about 1micron to about 15 microns, preferably about 3 microns to about 12microns.

Ranges of temperatures which can be sensed by the above exemplaryapparatus are on the order of about −10 degrees Celsius to about 1500degrees Celsius above ambient. Certainly lower temperatures, or highertemperatures, can be sensed by selecting infrared sensing apparatusdesigned for the respective higher or lower temperatures. However, ingeneral, the invention is practiced sensing temperatures in the range ofabout 10 degrees Celsius to about 200 degrees Celsius, preferably about15 degrees Celsius to about 100 degrees Celsius.

Assuming normal camera and processor sensitivity of the above equipmentas offered by the above suppliers, temperature differentials betweendifferent elements of web 44 which can be detected, whereby therespective edges of the respective elements can be seen on the visualdisplay, can be as small as about 0.1 degrees C. to about 10 degrees C.,preferably no more than about 0.2 degrees C. to about 5 degrees C.Smaller temperature differentials can be detected by providing forgreater sensitivity in camera 80, and/or higher levels of discriminationin processing apparatus 82.

In another less preferred embodiment, infrared sensor 80 can becomprised of an array of individual infrared sensors sensing differentbut contiguous portions of underlying web 44 and separately reporting toprocessing apparatus 82 the energy so sensed, whereupon processingapparatus 82 develops the composite visual image from the multiplesensors.

In the environment of fabrication line 10, appropriate shielding, ifneeded, can be placed about infrared sensor 80 to prevent heat fromnearby machinery from reaching the sensor and skewing the data beingcollected.

Infrared sensor 80 can be interfaced to processing apparatus 82 by knownvideo formats such as NTSC, RS-170 and VGA formats. These formats enableimage data to be sent from passive infrared sensor 80 in a form readableby process apparatus 82.

Process apparatus 82 comprises a computer module capable of comparingimages from infrared sensor 80 with preselected image values stored inthe computer or other memory storage device. One example of a processingapparatus 82 is the CHECKPOINT 800 (CVS-V816-000) produced by COGNEX ofNatick, Mass., USA.

The computer module in processing apparatus 82 can process the infraredsensor input images and provide outputs therefrom. Signal processing ofthe images can develop and define various visual images and imagesignatures specifically associated with specific processes forfabricating various specific personal care articles 78 being sensed bysensor 80 or a corresponding sensor array. The signatures are generallydefined by the amount of heat at various areas or zones of the personalcare article precursors 45 of web 44.

The greater the amount of heat at a given portion of the web, the darkerthat portion of the web appears in the visual image. In general, sensor80 is addressing a discrete length of the web, such as a length equal to1-2 lengths of precursors 45 along the length of the web, at any giventime. Along the length of web being sensed, sensor 80 senses thetemperatures based on an array of signals received from discrete,closely spaced areas of the personal care articles being assessed in theweb, and outputs signals, either serially or in tandem, representing thetemperatures so sensed about the area being assessed.

The sensing of the temperatures at the closely spaced discrete locationscan be done by taking a sequence of readings in serial order. In thealternative, the sensing at the closely spaced discrete locations can bedone by taking the multiple temperature readings simultaneously, using amultiplicity of sensor elements. The method used for collecting theinfrared data depends on the capability of the infrared instrumentsbeing used for data collection. Whichever data collection process isused, the multiple readings are combined in creating the visual image.

The signatures, namely the visual images, developed from the energysensed, are sent to operator station 104 where the visual images aredisplayed on e.g. a computer screen, and are preferably also comparedwith expected and/or standard signatures of the respective personal carearticle products. Different products made according to differentspecifications, of course, have correspondingly different signatures.For example, in the embodiment of FIG. 3, processing apparatus 82 cansend a signal to cull unit 102 to cull selected ones of personal carearticles having improper signatures. Such improper signatures can becaused by an out-of-tolerance improper location of one sensed componentrelative to another sensed component. Other improper signatures can becaused by too little or too much heat being sensed at a certainposition, for example, representing too little adhesive, a glob ofexcess adhesive, or an ineffective ultrasonic bond.

Signatures having threshold levels of variance from target parameterssuggest removal of the respective defective personal care articles 78 asby culling. Other signatures, showing lesser variances in one or moreparameters of one or more components of a personal care article, canresult in processing apparatus 82 sending signals to the variouselements of fabrication line 10. Such signals can cause a controllerinside or outside the respective device or unit to adjust the amount ofadhesive being applied to respective components of web 44 and/or toadjust the positions of one or more components, such as leg elastics,containment flaps, or the like, being secured to underlying web 44, ore.g. the amount of pressure being applied at one or more of the nips.

In addition or in the alternative, signature variances can lead toout-of-tolerance warning signals, in addition to the routine visualimage, being sent to an operator of the fabrication line machinery atoperator station 104. The warning signal can be audible, visual,tactile, or any combination of signal expressions designed to gain theattention of the operator. Such a warning signal can display orannounce, without limitation, the components identified as improper, thedirection and degree of variance and/or proposed corrective action, sothat the operator can make appropriate adjustments in the control systemof the fabrication line.

The visual image on e.g. the computer monitor can be refreshed at anydesirable frequency. Thus, the image can be continuously refreshed atthe maximum rate of updated information available through sensor 80 andprocessing apparatus 82. In the alternative, the image can be refreshedonly intermittently, such as once a minute, every 30 seconds, every 15seconds, or at any other desired interval within the capacity of sensor80 and processing apparatus 82.

While the description herein above, and the drawings, illustrate sensor80 and processing apparatus 82 as separate and individual apparatus, thefunctions of sensor 80 and processing apparatus 82 can be incorporatedinto a single piece of equipment if desired, such that the signalprocessing unit is housed in a common housing or enclosure along withthe sensing unit, as suggested by the dashed outline 106 about bothsensor 80 and processing apparatus 82 in FIG. 1. Indeed, such combinedhousing can be beneficial in that the overall space required in thesystem layout, or floor plan footprint, may be reduced thereby.

In some embodiments, the outer surface of second layer 32 has visiblefigures or symbols printed thereon. Such printed visual figures orsymbols are typically decorative in nature. While such printed visiblefigures or symbols interfere with product sensing using ultravioletlight or visible light for image sensing, such printed visible figuresor symbols do not interfere with the ability of infrared sensor 80 tosense thermal properties of elements underlying the printed images, andthus effectively sees through such printed figures or symbols, thus tocontinue to generate accurate images of the infrared signature in spiteof the printed visual figures or symbols.

FIGS. 4 and 5 illustrate cross-sections of precursors 45 of theinvention. FIG. 4 illustrates the cross-section toward the rear of thepersonal care article precursor, showing absorbent core 20 and ear 46 incross-section. FIG. 4 also shows bonds 90, 65 respectively at bothinward 91 and outward 63 edges of containment flaps 56 outside thecrotch region.

FIG. 5, by contrast, shows only the outward edges 63 of containmentflaps 56 bonded by bonds 65 in underlying web 44, whereby inward edge 91is free to stand up, away from second body-side liner layer 32 asillustrated in FIG. 6, and to interact directly with the body of thewearer when the personal care article is mounted on the body of awearer. Further, FIG. 5 illustrates locations of containment flaps 56and leg elastics 28 relative to the edges of leg cut-outs 96.

The invention has been described herein above in terms of incorporatinga number of specific elements or characteristics into personal carearticles, namely six specific elements (first layer 16, absorbent core20, leg elastics 28, second layer 32, tapes 46, and containment flaps56), plus adhesives, plus formation of ultrasonic bonds, in thefabrication process, to make personal care article precursors 45 andultimately personal care articles 78. Any number of elements orcharacteristics can be used, as desired, in fabricating the personalcare articles and wherein the invention comprehends assessing personalcare articles so fabricated. Thus, as few as one element (for examplebond location or bond strength) can be assessed. There is no upper limitto the number or type of elements or characteristics which can beassessed so long as the various elements or characteristics can bedistinguished from each other on the visual image, or otherwiseevaluated. Less than all relevant elements or characteristics can beassessed on a given visual image.

Referring to FIGS. 2, 7, and 8, the darker and wider the seal line onthe visual image, generally the more secure the seal. Correspondingly, arelatively narrower and lighter seal line indicates a relatively weakerseal. A relatively wider and darker seal line indicates a relativelystronger seal. Accordingly, either processing apparatus 82, or anoperator, can assess the strength of seals according to the combinationof width and darkness of the seal on the visual image.

A plurality of infrared sensor elements can be combined into a singleinfrared sensor instrument, wherein the several sensor elementscooperate with each other in defining the composite visual image, e.g.the image displayed on monitor 81.

A plurality of infrared sensors 80 can be positioned at a correspondingplurality of locations along the length of the fabrication line 10. Suchplurality of infrared sensors can all feed sensed data into a commonprocessing apparatus 82. In the alternative, the plurality of sensorscan feed sensed data into a plurality of processing apparatuses 82 (notshown), whereupon the plurality of processing apparatuses is coordinatedby a master controller (not shown).

The invention has been illustrated herein as a quality assessment ormanufacturing control tool. The invention can, as well, be used as aresearch and/or development tool for exploratory, non-destructiveevaluation to support, for example, tests of new materials, newassemblies, new element arrangements, new arrangements of old elements,and the like.

Further, the invention has been illustrated herein as having advantagefor sensing through a visually obstructive material which is, forexample opaque, translucent, or occlusive or the like. The invention isequally operable, and useful to advantage for sensing infraredproperties through clear, e.g. transparent materials which are emittinginfrared energy as described above.

As used herein, an “element” of personal care article 78 or personalcare article precursor 45 includes ultrasonic bonds and adhesive bonds,including adhesive employed for the purpose of making such bonds, aswell as the tangible elements having relatively fixed dimensions such asabsorbent core 20, tapes 46, and containment flaps 56.

Those skilled in the art will now see that certain modifications can bemade to the invention herein disclosed with respect to the illustratedembodiments, without departing from the spirit of the instant invention.And while the invention has been described above with respect to thepreferred embodiments, it will be understood that the invention isadapted to numerous rearrangements, modifications, and alterations, allsuch arrangements, modifications, and alterations are intended to bewithin the scope of the appended claims.

To the extent the following claims use means plus function language, itis not meant to include there, or in the instant specification, anythingnot structurally equivalent to what is shown in the embodimentsdisclosed in the specification.

Having thus described the invention, what is claimed is:
 1. A method ofsensing assembly quality characteristics of a web of personal carearticles or personal care article precursors being fabricated on afabrication line by processing apparatus, each personal care article orpersonal care article precursor having, as an element thereof, abodyside liner, an outer cover, and at least one element of the personalcare article or personal care article precursor disposed between thebodyside liner and the outer cover, the method comprising: (a) usinginfrared sensing and vision image signal processing apparatus employingan infrared sensor, sensing at least one quality characteristic of atleast one element of the personal care article or personal care articleprecursor, through an obstructive one of the elements of the personalcare article which precludes facile visual observation of the respectivequality characteristic, and outputting first signals from the infraredsensor; and (b) sending the outputted signals to an element of theinfrared sensing and vision image signal processing apparatus which canrespond by outputting second signals indicative of assembly qualitycharacteristics of the personal care articles or personal care articleprecursors being fabricated by the processing apparatus.
 2. A method asin claim 1, the infrared sensing and vision image signal processingapparatus comprising infrared sensor apparatus, and physicallyseparated, and distinct, signal processing apparatus receiving a signaloutputted from the infrared sensor apparatus and processing such signalto provide a processor output representative of at least one of thepersonal care articles or personal care article precursors fabricated onthe fabrication line.
 3. A method as in claim 1, the personal carearticle precursors comprising absorbent cores on the web, and bodysideliner material over the absorbent cores such that the absorbent coresare between the web and the bodyside liner material, the infraredsensing and vision image signal processing apparatus viewing and sensingthe position of the absorbent core through visually obstructivematerial.
 4. A method as in claim 3 wherein the visually obstructivematerial is one of the bodyside liner and the web.
 5. A method as inclaim 2, the personal care article precursors comprising absorbent coreson the web, and bodyside liner material over the absorbent cores suchthat the absorbent cores are between the web and the bodyside linermaterial, one of the bodyside liner material and the outer cover havinga first surface facing the infrared sensing and vision image signalprocessing apparatus, the first surface having a visual printed imagethereon, the sensing by the infrared sensing and vision image signalprocessing apparatus sensing an assembly quality characteristic underthe respective one of the outer cover and the bodyside liner material,through the visual printed image.
 6. A method as in claim 1, securementapparatus securing at least portions of the respective elements of thepersonal care articles to each other to form the composite personal carearticle precursors in a continuous web of such precursors joined to eachother along a length of the web, the infrared sensing and vision imagesignal processing apparatus sensing quality of such securement.
 7. Amethod as in claim 6, adhesive application apparatus applying adhesivefor securing at least first portions of first respective elements tosecond portions of second respective ones of the elements, the infraredsensing and vision image signal processing apparatus sensing theposition of the adhesive in the personal care articles.
 8. A method asin claim 7, the infrared sensing and vision image signal processingapparatus sensing quantities of adhesive disposed in the personal carearticles.
 9. A method as in claim 1, leg elastic placement apparatusplacing leg elastics, spaced from each other and adjacent respectiveopposing outside edges of leg cut-outs of respective ones of thepersonal care articles precursors, along the lengths of the personalcare articles, and adhering the leg elastics to elements of or on theweb, adhesive apparatus placing hot melt adhesive on the leg elastics,the infrared sensing and vision image signal processing apparatussensing the position of the hot melt adhesive on the leg elastic andthus indirectly detecting the positions of the leg elastics on thepersonal care articles.
 10. A method as in claim 9, the bodyside linerlayer being positioned between the infrared sensing and vision imagesignal processing apparatus and the leg elastics, the infrared sensingand vision image signal processing apparatus sensing the positions ofthe adhesive, and thus the positions of the leg elastics, through thebodyside liner layer.
 11. A method as in claim 1, the fabricationmachinery placing absorbent cores over the web as elements of thepersonal care article precursors, the absorbent cores having zonescomprising relative concentrations of superabsorbent, the infraredsensing and vision image signal processing apparatus sensing the zonesof relative concentration of superabsorbent as distinct from theremainders of the absorbent cores.
 12. A method as in claim 1, thefabrication machinery placing containment flaps over the web as elementsof the personal care article precursors, the containment flaps beingsecured in the web by hot melt adhesive, the infrared sensing and visionimage signal processing apparatus sensing position and quantity of thehot melt adhesive.
 13. A method as in claim 6, the securement apparatuscomprising an ultrasonic horn and cooperating anvil providing ultrasonicenergy to create bonds bonding, in the personal care article precursors,at least one of the elements of such personal care article precursors,such that the infrared sensing and vision image signal processingapparatus senses the bonds while the bonds are still warm from the bondforming process.
 14. A method as in claim 13, the infrared sensing andvision image signal processing apparatus sensing the positions of theultrasonic bonds.
 15. A method as in claim 13, the output of theinfrared sensing and vision image signal processing apparatus providingan indication to an operator station when the infrared sensing andvision image signal processing apparatus does not detect the presence ofthe ultrasonic bonds.
 16. A method as in claim 1, the infrared sensingand vision image signal processing apparatus sensing registrationpositioning of predetermined one or more of the elements.
 17. A methodas in claim 1, the output of the infrared sensing and vision imagesignal processing apparatus sending an alarm signal to an operatorstation identifying existence of an improper condition for at least oneof the elements.
 18. A method as in claim 1, the infrared sensing andvision image signal processing apparatus outputting a cull signal tocull selected ones of the personal care articles from the fabricationline.
 19. A method as in claim 1, the output of the infrared sensing andvision image signal processing apparatus shutting down the fabricationline.
 20. A method as in claim 1, the output of the infrared sensing andvision image signal processing apparatus calling attention tocharacteristics or elements of the personal care articles that are notwithin preselected control tolerances.
 21. A method as in claim 1, theinfrared sensing and vision image signal processing apparatus sensingthe presence of leg cut-outs on the personal care articles andcontrolling an alarm to an operator station.
 22. A method as in claim 1,the infrared sensing and vision image signal processing apparatussensing assembly quality characteristics common to the personal carearticles being fabricated on the fabrication line, the assembly qualitycharacteristics, in combination, comprising a signature for the personalcare articles being fabricated.
 23. A method as in claim 1, the infraredsensing and vision image signal processing apparatus sensing portions ofthe personal care articles having temperatures as low as about 10degrees Celsius and up to about 200 degrees Celsius.
 24. A method as inclaim 1, the infrared sensing and vision image signal processingapparatus comprising a passive infrared sensor sensing temperaturedifferences across the overall projected surface defined by an area ofone of the personal care articles.
 25. A method as in claim 1, theinfrared sensing and vision image signal processing apparatus comprisingan infrared camera collecting infrared images from the personal carearticles.
 26. A method as in claim 1, including outputting a signal fromthe infrared sensing and vision image signal processing apparatus, andfabricating a composite visual image representative of at least one ofthe personal care articles or personal care article precursors, from theso outputted signal.
 27. A method as in claim 26, the infrared sensingand vision image signal processing apparatus comprising an infraredcamera collecting, for each visual image, an array of infrared signalsfrom discrete areas of the respective personal care articles beingassessed.
 28. A method as in claim 1, including outputting, to anoperator station, a signal from the infrared sensing and vision imagesignal processing apparatus, the outputted signal representing anout-of-tolerance condition in the personal care article or personal carearticle precursor.
 29. A method as in claim 1, including maintaining thepersonal care articles free from fluorescent material and otheradditives for optical brightening as used for detection purposes,throughout fabrication of the personal care articles.
 30. A method as inclaim 1, the infrared energy received into the infrared sensing andvision image signal processing apparatus being received through apassive infrared sensor.
 31. A method of fabricating composite personalcare article products from precursor elements, at least one of theelements of precursors of the personal care article products sofabricated comprising a continuous web of material, the methodcomprising: (a) transporting the web along a fabrication line havingfabrication machinery, past a plurality of work stations where work isperformed on the web, for fabricating the personal care articleprecursors according to a predetermined arrangement, thereby to form anarray of precursors of such personal care articles on the web; (b)separating web segments, and the array of personal care articleprecursors thereon, from the web, and into individual personal carearticles, including severing the web across a transverse dimensionthereof; and (c) sensing infrared signatures of product work piecesfabricated on the web, creating a gray scale representation of thermaldifferences in the workpiece elements, and thereby determining assemblyquality characteristics of respective ones of the composite personalcare articles or composite personal care article precursors, andoutputting a signal representative of the determined assembly qualitycharacteristics.
 32. A method as in claim 31, infrared sensing andvision image signal processing apparatus comprising infrared sensorapparatus, and physically separate and distinct signal processingapparatus receiving a signal outputted from the infrared sensorapparatus and processing such signal to provide a processor outputrepresentative of at least one of the personal care articles or personalcare article precursors fabricated on the fabrication line.
 33. A methodas in claim 31, the fabrication machinery placing an absorbent core onthe web, and an bodyside liner material over the absorbent core suchthat the absorbent core is between the web and the bodyside linermaterial, infrared sensing and vision image signal processing apparatusviewing and sensing the position of the absorbent core through visuallyobstructive material.
 34. Fabrication apparatus as in claim 33 whereinthe visually obstructive material is one of the bodyside liner and theweb.
 35. A method as in claim 32, the fabrication machinery placing anabsorbent core on the web, and a bodyside liner material over theabsorbent core such that the absorbent core is between the web and thebodyside liner material, one of the bodyside liner material and the webhaving a first surface facing the infrared sensing and vision imagesignal processing apparatus, the first surface having a visual printedimage thereon, the sensing by the infrared sensing and vision imagesignal processing apparatus sensing an assembly quality characteristicunder the respective one of the bodyside liner material and the web,through the visual printed image.
 36. A method as in claim 32,securement apparatus securing at least portions of the respectiveelements of the personal care articles to each other to form thecomposite personal care article precursors in a continuous web of suchprecursors joined to each other along a length of the web.
 37. A methodas in claim 36, as to each of respective ones of the personal carearticles, adhesive application apparatus applying adhesive for securingat least a first portion of a first respective one of the elements to asecond portion of a second respective one of the elements.
 38. A methodas in claim 37, infrared sensing and vision image signal processingapparatus sensing the position of adhesive in the personal carearticles.
 39. A method as in claim 37, infrared sensing and vision imagesignal processing apparatus sensing quantities of adhesive disposed inthe personal care articles.
 40. A method as in claim 31, leg elasticplacement apparatus placing spaced leg elastics adjacent respectiveopposing outside edges of leg cut-outs of respective ones of thepersonal care article precursors, and adhering the leg elastics to suchpersonal care article precursors.
 41. A method as in claim 40, adhesiveapparatus placing hot melt adhesive on the leg elastics, infraredsensing and vision image signal processing apparatus sensing theposition of the hot melt adhesive on the leg elastic and thus indirectlydetecting the positions of the leg elastics on the personal carearticles.
 42. A method as in claim 41, the bodyside liner layer beingpositioned between the infrared sensing and vision image signalprocessing apparatus and the leg elastics, the infrared sensing andvision image signal processing apparatus sensing the positions of theadhesive, and thus the positions of the leg elastics, through thebodyside liner layer.
 43. A method as in claim 31, the fabricationmachinery placing absorbent cores over the web as elements of thepersonal care article precursors, the absorbent cores having zonescomprising relative concentrations of superabsorbent, infrared sensingand vision image signal processing apparatus sensing the zones ofrelative concentration of superabsorbent as distinct from the remaindersof the absorbent cores.
 44. A method as in claim 31, the fabricationmachinery placing containment flaps over the web as elements of thepersonal care article precursors, the containment flaps being secured inthe web by hot melt adhesive, infrared sensing and vision image signalprocessing apparatus sensing position and quantity of the hot meltadhesive.
 45. A method as in claim 36, the securement apparatuscomprising one of thermal apparatus and ultrasonic bonding apparatusproviding bonding energy to create bonds bonding, in the personal carearticle precursors, at least one of the elements of such personal carearticle precursors, such that infrared sensing and vision image signalprocessing apparatus senses the bonds while the bonds are still warmfrom the bond forming process.
 46. A method as in claim 45, the infraredsensing and vision image signal processing apparatus sensing thepositions of the ultrasonic bonds.
 47. A method as in claim 45, outputof the infrared sensing and vision image signal processing apparatusproviding an indication to an operator station when the infrared sensingand vision image signal processing apparatus does not detect thepresence of the ultrasonic bonds.
 48. A method as in claim 31, infraredsensing and vision image signal processing apparatus sensingregistration positioning of a predetermined one or more of the elements.49. A method as in claim 31, output of infrared sensing and vision imagesignal processing apparatus sending an alarm signal to an operatorstation identifying existence of an improper condition for at least oneof the elements.
 50. A method as in claim 31, infrared sensing andvision image signal processing apparatus outputting a cull signal tocull selected ones of the personal care articles from the fabricationline.
 51. A method as in claim 31, output of infrared sensing and visionimage signal processing apparatus shutting down the fabrication line.52. A method as in claim 31, output of infrared sensing and vision imagesignal processing apparatus calling attention to a characteristic orelement of the personal care articles which is not within preselectedcontrol tolerances.
 53. A method as in claim 31, infrared sensing andvision image signal processing apparatus sensing the presence of legcut-outs on the personal care articles and controlling an alarm to anoperator station.
 54. A method as in claim 31, infrared sensing andvision image signal processing apparatus sensing assembly qualitycharacteristics common to the personal care articles being fabricated onthe fabrication line, the assembly quality characteristics, incombination, comprising a signature for the personal care articles beingfabricated.
 55. A method as in claim 31, infrared sensing and visionimage signal processing apparatus sensing portions of the personal carearticles having temperatures as low as about 10 degrees Celsius to about200 degrees Celsius.
 56. A method as in claim 31, infrared sensing andvision image signal processing apparatus comprising a passive infraredsensor sensing temperature differences across the overall projectedsurface defined by an area of one of the personal care articles.
 57. Amethod as in claim 31, infrared sensing and vision image signalprocessing apparatus comprising an infrared camera collecting infraredimages from the personal care articles.
 58. A method as in claim 31,infrared sensing and vision image signal processing apparatus outputtinga signal useful to fabricate a composite visual image representative ofat least one of the personal care articles or personal care articleprecursors.
 59. A method as in claim 31, infrared sensing and visionimage signal processing apparatus comprising an infrared cameracollecting, for each visual image, an array of infrared signals fromdiscrete areas of the personal care articles being assessed.
 60. Amethod as in claim 31, infrared sensing and vision image signalprocessing apparatus outputting a signal, representing anout-of-tolerance condition in the personal care article or personal carearticle precursor, to an operator station.
 61. A method as in claim 31,including maintaining the personal care articles free from fluorescentmaterial and other additives for optical brightening as used fordetection purposes.
 62. A method as in claim 31, including comparing thesensed signal to a signal standard.